There is a wide difference of opinion as to the classification of mushrooms. Perhaps the most simple and satisfactory is that of Underwood and Cook. They arrange them under six groups:
- Basidiomycetes—those in which the spores or reproductive bodies are naked or external as shown in illustration 2 on page 15.
- Ascomycetes—those in which the spores are inclosed in sacs or asci. These sacs are very clearly represented in illustration Figure 4 on page 18. This will include the Morels, Pezizæ, Pyrenomycetes, Tuberaceæ, Sphairiacei, etc.
- Physcomycetes—including the Mucorini, Saprolegniaceæ, and Peronosporeæ. Potato rot and downy mildew on grape vines belong to this family.
- Myxomycetes—Slime moulds.
- Saccharomycetes—Yeast fungi.
- Schizomycetes—are minute, unicellular Protophytes which reproduce mainly by transverse fission.
Class, Fungi—Sub-Class, Basidiomycetes.
This class will include all gill-bearing fungi, Polyporus, Boletus, Hydnum, etc.
Fungi of this class are divided into four natural groups:
- Hymenomycetes.
- Gasteromycetes.
- Uredinæ.
- Ustilagineæ.
Group 1—Hymenomycetes.
Under this group will be placed all fungi composed of membranes, fleshy, woody, or gelatinous, whether growing on the ground or on wood. The hymenium, or spore-bearing surface, is external at an early stage in the life of the plant. The spores are borne on basidia as explained in Figure 2, page 6. When the spores ripen they fall to the ground or are carried by the wind to a host that presents all the conditions necessary for germination; there they produce the mycelia or white thread-like vines that one may have noticed in plowing sod, in old chip piles, or decayed wood. If one will examine these threads there will be found small knots which will in time develop into the full grown mushroom. Hymenomycetes are divided into six families: